#ifndef _RWC_ANALYZE_HEADER_ /*************************************************************************** From http://www.mayo.edu/bir/Analyze_Pages/AnalyzeFileInfo.html Describes the ANALYZE 7.5 file format (.img/.hdr pairs). ---------------------------------------------------------------- The image database is the system of files that the ANALYZE package uses to organize and access image data on the disk. Facilities are provided for converting data from a number of sources for use with the package. A description of the database format is provided to aid developers in porting images from other sources for use with the ANALYZE TM system. An ANALYZE image database consists of at least two files: * an image file * a header file The files have the same name being distinguished by the extensions .img for the image file and .hdr for the header file. Thus, for the image database heart, there are the UNIX files heart.img and heart.hdr. The ANALYZE programs all refer to this pair of files as a single entity named heart. Image File The format of the image file is very simple containing usually uncompressed pixel data for the images in one of several possible pixel formats: * 1 bit packed binary (slices must begin on byte boundaries) * 8 bit 8 bits per pixel (unsigned char) * 16 bit 16 bits per pixel (signed short) * 32 bit 32 bits per pixel signed integers, or floating point * 64 bit 64 bits per pixel; double precision, floating point, or complex. * 24 bit RGB , 8-bits per channel Red, Green, Blue. Header File The header file is represented here as a `C' structure which describes the dimensions and history of the pixel data. The header structure consists of three substructures: header_key describes the header image_dimension describes image sizes data_history optional ****************************************************************************/ struct header_key /* header key */ { /* off + size */ int sizeof_hdr; /* 0 + 4 */ char data_type[10]; /* 4 + 10 */ char db_name[18]; /* 14 + 18 */ int extents; /* 32 + 4 */ short int session_error; /* 36 + 2 */ char regular; /* 38 + 1 */ char hkey_un0; /* 39 + 1 */ }; /* total=40 bytes */ struct image_dimension { /* off + size */ short int dim[8]; /* 0 + 16 */ short int unused8; /* 16 + 2 */ short int unused9; /* 18 + 2 */ short int unused10; /* 20 + 2 */ short int unused11; /* 22 + 2 */ short int unused12; /* 24 + 2 */ short int unused13; /* 26 + 2 */ short int unused14; /* 28 + 2 */ short int datatype; /* 30 + 2 */ short int bitpix; /* 32 + 2 */ short int dim_un0; /* 34 + 2 */ float pixdim[8]; /* 36 + 32 */ /* pixdim[] specifies the voxel dimensitons: pixdim[1] - voxel width pixdim[2] - voxel height pixdim[3] - interslice distance ...etc */ float vox_offset; /* 68 + 4 */ float funused1; /* 72 + 4 */ float funused2; /* 76 + 4 */ float funused3; /* 80 + 4 */ float cal_max; /* 84 + 4 */ float cal_min; /* 88 + 4 */ float compressed; /* 92 + 4 */ float verified; /* 96 + 4 */ int glmax,glmin; /* 100 + 8 */ }; /* total=108 bytes */ struct data_history { /* off + size */ char descrip[80]; /* 0 + 80 */ char aux_file[24]; /* 80 + 24 */ char orient; /* 104 + 1 */ char originator[10]; /* 105 + 10 */ char generated[10]; /* 115 + 10 */ char scannum[10]; /* 125 + 10 */ char patient_id[10]; /* 135 + 10 */ char exp_date[10]; /* 145 + 10 */ char exp_time[10]; /* 155 + 10 */ char hist_un0[3]; /* 165 + 3 */ int views; /* 168 + 4 */ int vols_added; /* 172 + 4 */ int start_field; /* 176 + 4 */ int field_skip; /* 180 + 4 */ int omax, omin; /* 184 + 8 */ int smax, smin; /* 192 + 8 */ }; struct dsr { struct header_key hk; /* 0 + 40 */ struct image_dimension dime; /* 40 + 108 */ struct data_history hist; /* 148 + 200 */ }; /* total= 348 bytes*/ /* Acceptable values for datatype */ #define ANDT_NONE 0 #define ANDT_UNKNOWN 0 /* what it says, dude */ #define ANDT_BINARY 1 /* binary (1 bit/voxel) */ #define ANDT_UNSIGNED_CHAR 2 /* unsigned char (8 bits/voxel) */ #define ANDT_SIGNED_SHORT 4 /* signed short (16 bits/voxel) */ #define ANDT_SIGNED_INT 8 /* signed int (32 bits/voxel) */ #define ANDT_FLOAT 16 /* float (32 bits/voxel) */ #define ANDT_COMPLEX 32 /* complex (64 bits/voxel) */ #define ANDT_DOUBLE 64 /* double (64 bits/voxel) */ #define ANDT_RGB 128 /* RGB triple (24 bits/voxel) */ #define ANDT_ALL 255 #define ANDT_string(aa) \ ((aa)==ANDT_BINARY ? "binary" \ :(aa)==ANDT_UNSIGNED_CHAR ? "byte" \ :(aa)==ANDT_SIGNED_SHORT ? "short" \ :(aa)==ANDT_SIGNED_INT ? "int" \ :(aa)==ANDT_FLOAT ? "float" \ :(aa)==ANDT_COMPLEX ? "complex" \ :(aa)==ANDT_DOUBLE ? "double" \ :(aa)==ANDT_RGB ? "RGB" \ : "unknown" ) /*************************************************************************** The header format is flexible and can be extended for new user-defined data types. The essential structures of the header are the header_key and the image_dimension. The required elements in the header_key substructure are: int sizeof_header Must indicate the byte size of the header file. int extents Should be 16384, the image file is created as contiguous with a minimum extent size. char regular Must be `r' to indicate that all images and volumes are the same size. The image_dimension substructure describes the organization and size of the images. These elements enable the database to reference images by volume and slice number. Explanation of each element follows: short int dim[]; = array of the image dimensions dim[0] = Number of dimensions in database; usually 4 dim[1] = Image X dimension; number of pixels in an image row dim[2] = Image Y dimension; number of pixel rows in slice dim[3] = Volume Z dimension; number of slices in a volume dim[4] = Time points, number of volumes in database. char vox_units[4] = specifies the spatial units of measure for a voxel char cal_units[4] = specifies the name of the calibration unit short int datatype = datatype for this image set Acceptable values for datatype are one of the ANDT_* defines above short int bitpix = number of bits per pixel; 1, 8, 16, 32, 64 short int dim_un0 = unused float pixdim[] = Parallel array to dim[], giving real world measurements in mm and ms. pixdim[1] = voxel width in mm pixdim[2] = voxel height in mm pixdim[3] = slice thickness in mm float vox_offset = byte offset in the .img file at which voxels start. This value can be negative to specify that the absolute value is applied for every image in the file float cal_max, = specify the range of calibration values cal_min int glmax, glmin = The maximum and minimum pixel values for the entire database The data_history substructure is not required, but the orient field is used to indicate individual slice orientation and determines whether the Movie program will attempt to flip the images before displaying a movie sequence. orient = slice orientation for this dataset. 0 = transverse unflipped 1 = coronal unflipped 2 = sagittal unflipped 3 = transverse flipped 4 = coronal flipped 5 = sagittal flipped ****************************************************************************/ #endif /* _RWC_ANALYZE_HEADER_ */